G218A GMT | Alldatasheet
Document overview
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Technical content
Features
Auto-selectable multi-mode Single-Ended or LVD Termination Meets SCSI-1, SCSI-2, SCSI-3 SPI Ultra (Fast-20), Ultra 2(SPI-2 LVD), Ultra160 stan- dards. Supports active negation Current limit and thermal protection Hot-Swap compatible (Single-Ended) 5% tolerance on SE and LVD termination resistance 28 and 36 pin SSOP package 28 Pin SSOP: Pin Compatible with DS2119 36 Pin SSOP: Pin Compatible with DS2118, LX5241 and UCC5630
Applications
Server and workstation High-end PC Industrial PC Disk Array (RAID) SCSI cable General Description The G218A Multi-mode LVD/SE SCSI terminator pro- vides a smooth transition into the next generation of the SCSI Parallel Interface (SPI-2). It automatically senses the bus, via DIFFSENS, and switches the ter- mination to either single-ended (SE) or low voltage differential (LVD) SCSI, dependent on which type of devices are connected to the bus. If the G218A de- tects a HVD SCSI device, it switches to a high imped- ance state. For a 16-bit Wide SCSI bus to be opera- tional, three G218A terminators are needed. The Multi-mode terminator contains all functions re- quired to terminate and auto detect and switch modes for SCSI parallel Interface (SPI-2) bus architectures. For the SE termination, one regulator and nine preci- sion 110ohm resistors are used. For the LVD termina- tion, the G218A integrates two regulated supplies with nine precision resistor strings. Pin Configuration (Top View) NC NC R1+ R1- R2- HS/GND HS/GND R3+ R3- R4+ R4- R5+ R5- DISCNCT GND TPWR HVD LVD SE R9- R9+ R8- R8+ HS/GND HS/GND HS/GND R7- R7+ R6- R6+ DIFFB DIFFSENSE M/S VREF R2+ HS/GND 36Pin SSOP G218A 34NC NC R1+ R1- R2- HS/GND HS/GND R3+ R3- R4+ R4- R5+ R5- DISCNCT GND TPWR HVD LVD SE R9- R9+ R8- R8+ HS/GND HS/GND HS/GND R7- R7+ R6- R6+ DIFFB DIFFSENSE M/S VREF R2+ HS/GND 36Pin SSOP G218A R1- R1+ R2- NC R3+ R3- R4+ R4- R5+ R5- DISCNCT GND TPWR R9- R9+ R8+ R8- R7- R6- R6+ DIFFB DIFFSENSE M/S 28Pin SSOP/TSSOP VREF R2+ TPWR R7+ G218A NC
Ver 3.3 Sep 11, 2001 TEL: 886-3-5788833 http://www.gmt.com.tw G218A Global Mixed-mode Technology Inc.
Ordering Information
PART NUMBER TEMP. RANGE PIN-PACKAGE FEATURE G218AT-S4 0ºC-70ºC SSOP-28 pin / Tube DISCNCT does not disable VREF G218AR-S4 0ºC-70ºC SSOP-28 pin / Tape & Reel DISCNCT does not disable VREF G218AT-S5 0ºC-70ºC SSOP-36 pin / Tube DISCNCT does not disable VREF G218AR-S5 0ºC-70ºC SSOP-36 pin / Tape & Reel DISCNCT does not disable VREF G218AT-D3 0ºC-70ºC TSSOP-28 pin / Tube DISCNCT does not disable VREF G218AR-D3 0ºC-70ºC TSSOP-28 pin / Tape & Reel DISCNCT does not disable VREF Functional Description The G218A combines LVD and SE termination with DIFFSENS sourcing and detection. The LVD termina- tion section consists of two source/sink amplifiers (VTOP, VBOT), biasing circuitry and nine precision resistor strings (RTOP, RMID, RBOT). The SE termi- nation section consists of a 2.85V source/sink regula- tor with 9 precision 110ohm resistor. The DIFFSENSE section consists of a 1.3V, 5mA driver and a sensing circuit (Figure 1) DIFFSENSE is used by multi-mode transceiver (LVD/SE) to determine if the device is connected to a single-ended, LVD or HVD SCSI bus. If the voltage on DIFFSENSE is between 0-0.5V the bus is sin- gle-ended; if it is between 0.7-1.9V the bus is LVD; and if it is greater than 2.4V, the bus is HVD. The G218A DIFFB pin monitors the DIFFSENS line to determine the proper operating mode of the device; this mode is indicated by the SE/LVD/HVD outputs. The DIFFSENSE pin can also drive the SCSI DIFFSENS line (when M/S=1) to determine the SCSI bus operating mode. The G218A switches to the ter- mination mode that is appropriate for the bus based on the value of the DIFFSENS voltage. These modes are: LVD mode LVD termination is provided by a precision resistor string with two amplifiers. This configuration yields a 105 Ω differential and 150 Ω common mode impedance. A fail safe bias of 112mV is maintained when no drivers are connected to the SCSI bus. SE mode When the external driver for a given signal line turns off, the active terminator will pull that signal line to 2.85 volts (quiescent state). When used with an active negation driver, the power amp can sink 22mA per line. while keeping the voltage reference in regulation. The terminating resistors maintain their 110Ω value. HVD Isolation Mode The G218A identifies that there is an HVD (high voltage differential) device on the SCSI bus and isolates the termination pins from the bus. When DISCNCT=1, the termination pins are isolated from the SCSI bus, and the bus mode indicators (SE/LVD/HVD) as well as VREF remains active. Dur- ing thermal shutdown, the termination pins are isolated from the SCSI bus and VREF becomes high imped- ance. The DIFFSENSE driver is shut down during ei- ther of these two events. To ensure proper operation, the TPWR pin should be connected to the SCSI bus TERMPWR line. As with all analog circuitry, the TERMPWR and VDD lines should be bypassed locally. A 2.2µF capacitor and a 0.01µF high frequency capacitor is recommended between TPWR and ground and placed as close as possible to the G218A. The G218A should be placed as close as possible to the SCSI connector to minimize signal and power trace length, thereby resulting in less input ca- pacitance and reflections which can degrade the bus signals. To maintain the specified regulation, a 4.7µF capacitor is required between the VREF pin and ground of each G218A. A high frequency cap (0.1µF ceramic recom- mended) can also be placed on the VREF pin in ap- plications that use fast rise/fall time drivers. A typical SCSI bus configuration is shown in Figure2. An internal pull down resistor assures that the G218A will be terminating the bus if the DISCNCT pin is left floating. Note: DIFFSENS Refers to the SCSI bus signal. DIFFSENSE Refers to the G218A pin name and in- ternal circuitry relating to differential sensing. DIFFB Refers to the G218A pin name and internal circuitry relating to monitoring the DIFFSENS line.
Ver 3.3 Sep 11, 2001 TEL: 886-3-5788833 http://www.gmt.com.tw G218A Global Mixed-mode Technology Inc. G218A Block Diagram (Figure 1) DIFFB DIFFSENSE SE LVD HVD THERMAL SHUTDOWN CIRCUITRY DISCNCT M/S CONTROL LOGIC VREF DIFFSENSE CIRCUITRY SE LVD HVD BANDGAP REFERENCE VREF
110 Ohms
( ) DIFFB DIFFSENSE SE LVD HVD THERMAL SHUTDOWN CIRCUITRY DISCNCT M/S CONTROL LOGIC VREF DIFFSENSE CIRCUITRY SE LVD HVD BANDGAP REFERENCE VREF +_+_ ( )
Ver 3.3 Sep 11, 2001 TEL: 886-3-5788833 http://www.gmt.com.tw G218A Global Mixed-mode Technology Inc. SCSI Bus Configuration (Figure 2) G218A G218A G218A G218A TPWR M/S DISCNCT DIFFSENSE CONTROL LINES (9) DIFFSENS TPWR TERMPWR 20K VREF DIFFB 0.1µF DIFFSENSE DIFFB VREF TERMPWR TPWR M/S DISCNCT DIFFB VREF TPWR DIFFB VREF TPWR DATA LINES (9) VREF DIFFB TPWR VREF DIFFB DATA LINES (9) G218AG218A 2.2µF 2.2µF 2.2µF 2.2µF 2.2µF 2.2µF M/S DISCNCT M/S DISCNCT M/S DISCNCT M/S DISCNCT 4.7µF 4.7µF 4.7µF 4.7µF 4.7µF 4.7µF 0.1µF 20K G218A G218A G218A G218A TPWR M/S DISCNCT DIFFSENSE CONTROL LINES (9) DIFFSENS TPWR TERMPWR 20K VREF DIFFB 0.1µF DIFFSENSE DIFFB VREF TERMPWR TPWR M/S DISCNCT DIFFB VREF TPWR DIFFB VREF TPWR DATA LINES (9) VREF DIFFB TPWR VREF DIFFB DATA LINES (9) G218AG218A 2.2µF 2.2µF 2.2µF 2.2µF 2.2µF 2.2µF M/S DISCNCT M/S DISCNCT M/S DISCNCT M/S DISCNCT 4.7µF 4.7µF 4.7µF 4.7µF 4.7µF 4.7µF 0.1µF 20K
Ver 3.3 Sep 11, 2001 TEL: 886-3-5788833 http://www.gmt.com.tw G218A Global Mixed-mode Technology Inc. Pin Description (for 28pin SSOP) PIN SYMBOL DESCRIPTION 1 VREF* Reference Voltage. 2.85-volt reference; a regulator bypass, must be connected to a 4.7µF capacitor. 2-5,7-12, Signal Termination. (X=1,2,3,…..9) Rx+: Ground line for single-ended or positive line for differential applications for the SCSI bus. Rx-: Signal line/active line for single-ended or negative line in differential applications for the SCSI bus. 6,22 NC No Connect. Do not connect these pins. 13 DISCNCT Disconnect. When pulled high, the G218 isolates its bus pins (Rx+, Rx-) from the SCSI bus. 14 GND Ground. Terminator ground pin. Connected to ground. 15 M/S Master/slave. Used to select which terminator is the controlling device. M/S pin high enables the DIFFSENSE driver. 16 DIFFSENSE Output to drive the SCSI bus DIFFSENS line.
17 DIFFB
DIFFB pin should be connected to a 0.1µF capacitor to GND and 20k resistor to SCSI/Bus DIFFSENS line. An input pin to detect the type of device (differential or single-ended) on the SCSI bus. 27,28 TPWR Terminator Power. Connect to the SCSI TERMPWR line and de-couple with a 2.2µF capacitor. *The VREF keeps the level at 2.85 volt, despite the DISCNCT pin is asserted or not; even the termination mode is changed. (36pin SSOP) PIN SYMBOL DESCRIPTION 1 VREF* Reference Voltage. 2.85-volt reference; a regulator bypass, must be connected to a 4.7µF capaci- tor. 2,3 NC No Connect. Do not connect these pins. 4-7,11-16, 22-25, 29-32 Rx+ Rx- Signal Termination. (X=1,2,3,…..9) Rx+: Ground line for single-ended or positive line for differential applications for the SCSI bus. Rx-: Signal line/active line for single-ended or negative line in differential applications for the SCSI bus. 8, 9,10,26, 27,28 HS/GND Heat Sink Ground. Connect to large area PC board traces to increase power dissipation capabil- ity. 17 DISCNCT Disconnect. When pulled high, the G218 isolates its bus pins (Rx+, Rx-) from the SCSI bus. 18 GND Ground. Terminator ground pin. Connected to ground. 19 M/S Master/slave. Mode select for the non controlling terminator. MSTR enables the DIFFSENSE driver. 20 DIFFSENSE Output to drive the SCSI bus DIFFSENS line.
21 DIFFB
DIFFB pin should be connected to a 0.1µF capacitor to GND and 20k resistor to SCSI/Bus DIFFSENS line. An input pin to detect the type of device (differential or single-ended) on the SCSI bus. 33 SE Single ended mode indicator. It is HIGH when terminator is operating in SE mode. 34 LVD Low Voltage Differential mode indicator. It is HIGH when terminator is operating in LVD mode. 35 HVD High Voltage Differential mode indicator. It is HIGH when terminator is operating in HVD mode or thermal shutdown. 36 TPWR Terminator Power. Connect to SCSI bus TERMPWR line and decouple with 2.2µF capacitor. *The VREF keeps the level at 2.85 volt, despite the DISCNCT pin is asserted or not; even the termination mode is changed.
Ver 3.3 Sep 11, 2001 TEL: 886-3-5788833 http://www.gmt.com.tw G218A Global Mixed-mode Technology Inc. Recommended Operating Conditions PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Termpower Voltage V tpwr 4.5 5 5.50 V Logic 0 V il -0.3 +0.8 V Logic 1 V ih 2.0 V tpwr+0.3 V Operating Temperature T amb 0 70 °C S i n g l e E n d e d C h a r a c t e r i s t i c s (0°C to 70°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES SE Termination Resistance Rse 104.5 110 115.5 Ohms Vline = 0-3.0 volts SE Voltage Reference Vref 2.79 2.85 2.93 Volts SE output Current Iose 25.4 mA Vline = 0.2 volts L o w V o l t a g e D i f f e r e n t i a l C h a r a c t e r i s t i c s (0°C to 70°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Differential Mode Termination Resistance Rdm 100 105 110 Ohms Common Mode Termination Resistance Rcm 110 150 190 Ohms Differential Mode Bias Vdm 100 112 125 mV All lines Open Common Mode Bias Vcm 1.125 1.25 1.375 V D C C h a r a c t e r i s t i c s (0°C to 70°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Termpower Current I tpmr 35 mA All lines Open Input Leakage High I ih -1.0 µA Input Leakage Low I il 1.0 µA Output Current High I oh -1.0 mA V out = 2.4 volts;SE/LVD/HVD Pins only Output Current Low I ol 4.0 mA V out=0.4 volts;SE/LVD/HVD Pins only DIFFSENS SE Operating Range V seor -0.3 0.5 V DIFFSENS LVD Operating Range V lvdor 0.7 1.9 V DIFFSENS HVD Operating Range V hvdor 2.4 V tpwr+0.3 V DIFFSINS Driver Output Voltage V dso 1.2 1.4 V M/S=1; I ds = 0-5mA DIFFSENSE Driver Source Current I dsh 5 15 mA M/S = 1; V dso=0V DIFFSENSE Driver Sink Current I dsl 20 200 µA M/S=1; V dso=2.75V R e g u l a t o r C h a r a c t e r i s t i c s (0°C to 70°C) PARAMETER SYMBOL MIN TYP MAX UNITS NOTES Line Regulation LI REG 1.0 2.0 % Load Regulation LO REG 1.3 3.0 % Current Limit I LIM 350 mA Sink Current I SINK 200 mA
Ver 3.3 Sep 11, 2001 TEL: 886-3-5788833 http://www.gmt.com.tw G218A Global Mixed-mode Technology Inc. Package Information (28 pin SSOP) E1 E D e b A C
1.00 REF
L 0.25 θ
Ver 3.3 Sep 11, 2001 TEL: 886-3-5788833 http://www.gmt.com.tw G218A Global Mixed-mode Technology Inc. 36 pin SSOP b 0.300 0.450 0.012 0.018 c 0.127 0.254 0.005 0.010 e 0.800 BASIC 0.032 BASIC E 10.033 10.668 0.395 0.420 h 0.381 0.635 0.015 0.025 L 0.508 1.016 0.020 0.040 θ 0 8 0 8 h x 45° C L θ E1 E SEATING PLANE 0.004 C D be A
Ver 3.3 Sep 11, 2001 TEL: 886-3-5788833 http://www.gmt.com.tw G218A Global Mixed-mode Technology Inc. 28 pin TSSOP Note: 1. Package body sizes exclude mold flash protrusions or gate burrs 2. Tolerance ±0.1mm unless otherwise specified 3. Coplanarity : 0.1mm 4. Controlling dimension is millimeter converted inch dimensions are not necessarily exact. 5. Followed from JEDEC MO-153 DIMENSION IN MM DIMENSION IN INCH Taping Specification E1 E D b A C L θ e Feed Direction Typical SSOP, TSSOP Package Orientation Feed Direction Typical SSOP, TSSOP Package Orientation